Recording and reproducing sound



June 25, 1929. v HUTCHISQN 1,718,355

AMPuHEe Filed Feb. 24, 1927 N VEN TOR.

, ATTORNEY 7 may be conveniently stored on a v wound upon a second, or take-up reel.

, indlependent of the amount of wireon either Patented Junez s, 1929. 1,718,355 UNITED STATES PATENT OFFICE.

MILLER REESE HUTCHISON, OF LLEWELLYN PARK, WEST- ORANGE, NEW JERSEY,-

ASSIGNMENTS, T0 ACOUSTIC PRODUCTS COMPANY, OF NEW YORK, N. Y., A CORPORATION OF DELAWARE.

RECORDING AND REPRODUCING SOUND. Application filed February 24, 1927. Serial No. 170,445.

This invention relates to an improved method of and means for recording and reproducing sound.

he invention has particular reference to the recording and reproducing of sound by means of a movable body of indeterminate length actuated at a predetermined rate of speed. The movable body may take the form of a magnetizahle wire variably magnetized throughout its length. This wire reel, and when being magnetized, as during the re-. cording operation, or when being used for sound reproduction, the wire is drawn from the storage reel, moved into proximity with magnetically responsive devices, and. is then will be identified by specific names for convenience of expression, but they are intended to be as generic in their application to similar parts or equivalent construction as the art will permit.

eferring to the drawing, there is shown a source of power, in the form of power mains 10, 11 connected to a power control switch 12. One contact point of the power control switch is connected by way of a conductor 13 to one field winding terminal 14 of a motor 15, the other field terminal 16 of which is connected by a conductor 17 to the other contact point of the power control switch 12. Thus the field winding of the motor 15 is energized from the power source henever the switch 12 is closed. The motor 15 is preferably a motor of the direct current shunt wound ty 0.

The armature of the motor 15 is direct connected to a shaft 20, and is usual brushes 21, 22 in a conventional manner. ()ne brush 21 is connected, as by a conductor 23 to a contact blade 24 of a switch 25. In the upper position of the switch 25 the blade 24 makes connection with a contact connected to the conductor 13, and thus to one pole of the powersource. The other brush 22 is connected by way of a. conductor 27 to a blade 28 of the switch 25,

At the beginning of the effective diameter of the take-up reel is small and that of the storage or follower reel is great; while near the end of an operation the reverse condition holds. Nevertheless, in order to preserve the faithfulness of reproduction and inte rity of pitch which I is required for high qua ity performance, it is extremely important that the linear speed of travel of the wire with respect to the magnetically responsive means shall be constant. The present invention effectively maintains such a constant speed With great accuracy,

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The structure herein disclosed alsoa'voids variations in speed due to friction in the reel supports, or other variable factors, and the is in its lower closed position the blades 24, speed of operation remains substantially 28 are electrically. connected to ether by way engages a contact 29 power source 10, 11. hen t he switch 25 constant independent thereo of a strap 30, so as to short cirguit the motor Another important feature of the invenarmaturetion relates to the control of the follower The shaft 20 is rotatably mounted in suitreel, so that even when the machine is able stopped, as in the middle of a record,- the follower reel is effectively prevented from over-running and the wire is held taut at all times. The wire is thus prevented from being snarled or kinked. Other objects will appear from the following description and claims taken in con- 1 -,nection with the accompanying .drawings in thereto a grooved sheave or drum 40. The grooves of the drum 40 are commensurate in size with the wire which is'to formthe sound record. Asshown a wire 41, formed 0 ower reel 42, which is keyed to a rotatable shaft 43, mounted in suitable bearings (not which there is shown A shown). A similar shaft 44 is rotatably diagrammatic p'ers ective view of a mounted in alinement'with the shaft 43, and mechanlsm embodying eatures of the inis provided with a-take up reel 45 upon vention.

at the completion of the operation. The first shaft 43 terminates in an armature 46 forming part of a In the following description and claims, parts, characteristic features and functions which in the upper position of the switch bearings (not shown) and has affixed I gang . the conductor 13.

series wound motor'47.' The motor 47 is provided with a field 48, which with its poles, yoke, and coils, rotatcs in space. The field 48 is afiixed to the shaft 44. The motor 47 thus forms an electrical differential connection between the reels 42, 45.

The field of the motor 47 is wired to a 'pair of collecting brushes 50, 51. The brush 50 is connected over a conductor 52 to a blade 53 of the switch 25, the upper contact 54 engaged thereby being directly connected to The lower contact engaged thereby is connected to the same conductor through a current limiting resistance 55. The other brush 51 is connected by a conductor 56 to a'blade 57 of the switch 25, which engages in the upper position of the switch a contact 58. The cont-act 58 is connected by conductor 59 to a collecting brush 60 and thus to an armature brush 61 of the motor 47. In its lower position the blade 57 engages a contact 62 connected to the conductor 17 The other brush 63 of the armature is connected through a collecting'brush 64, over a conductor 65 to a blade 66. of the switch 25. In the upper position of the switch the blade 66 engages a contact 67 connected to the conductor 17 In the lower position it engages a contact 68 connected to the conductor 59.

The shaft 43 is provided with a, brake drum 70 having in normal frictional contact therewith a spring pressed shoe 71 which includes an armature of a brake release magnet 72. Similarly, the shaft 44 18 provided with a brake drum 73 engaged by a shoe 74 and having a brake release magnet 75. The

magnets 72 and 75 are connected in'series with each other and with a blade 76 of the switch 25, and thus to the conductors'13, 17, so that when switch 12 is closed, and the switch 25 is closed in its upper position, the magnets are energized and the brakes released.

In passing from the drum 40 to'the take up reel 45 the wire 41 moves in proximity to and preferably between the.poles of a pair of magnets 80, 81, which are fixed in space and the coils of which are connected in series and to conductors 82,83 extending to switch contacts 84, respectively. \Vhen the switch is in the lower position as shown the magnets 80, 81 are in circuit with a telephone transmitter 86 and .a source of energy such as a battery 87. hen the switch is moved to its upper position, the

v magnets 80, 81 are in circuit with a telephone receiver or loud speaker 88.

Parallel to the shaft 20 is a rotatable idler or jack shaft 101 journalled on suitable bearings (not shown). A drum 102 is afiixed to the shaft 101 having grooves similar to the grooves of the drum 40. The artitionsseparating the grooves of the i ler drum 102 are in alinement with the grooves of the drum thereof.

In operation, assuming first that the switches 12, 25, and 76 are open a full reel of wire is applied to the shaft 43. The end of the wire 41 is then threaded around the grooves of the drums 40 and 102 and is passed. between the pole pieces of the magnets 80, 81 and is secured to the take-up reel 45. The switch contacts 84, 85 are placed in their down position as shown. Assuming that the wire 40 has had no previous record placed thereon, the apparatus is now ready for the recording of sound.

The switch 12 is now closed; and the switch 25 is closed in its upper position. Current now flows from one of the poles 10 of the power source, right hand blade of the switch 12, conductor 13, field terminal 8 of the motor 15, field winding thereof, terminal 16, conductor 17, left hand blade of the switch 12 to the other pole 11 of the power source. Current flows fromthe conductor 13 through the blade 24 of the switch 25, conductor 23, brush 21 through the armature Current flows from the blade 76 of the switch 25, windings of the brake release magnets 72,v

75 in series, to the conductor 17, thus energizing the brake release magnets and releasing the shoes 74, 71. Current also flows from the conductor 13, contact 54, blade .53 of the switch 25, conductor 52, field winding 48 of the motor 47, conductor 56, blade 57 of the switch 25, conductor 59, armature of the motor 47 conductor 65, switch blade 66 of the switch 25, to the conductor 17 thus energizing the field and the armature of the motor 47 in series.

The motor 15 now drives the shaft 20 and rotates the drum 40 in a clockwise direction. This pulls the wire 41 from the storage reel 42. motor 47 functions in a double capacity, 1. e. to oppose the clockwise rotation imparted to the storage spool 42 by the pulling of the wire 41 therefrom and also to rotate the takeup reel 45 in a clockwise direction so as to wind the wire thereon'as it comes from the drum 40.

Thus the wire 41 is driven in proximity to the magnets 80, 81 at a suitable constant linear velocity. The transmitter 86 is acted upon by the music which is to be recorded, and'produces electrical undulations in the circuits of the magnets 80, 81 corresponding to the compressional waves impinging thereon. This undulatory electrical energy proof the shaft 20 in a.

At the same time the series .wound the wire 41 accordingly. continued until the desired record iswmade or until the entire length of wire has been withdrawn from the storage reel lVhcn it is desired to discontinue the making of a record, the switch is rapidlyshifted to its down position. ing of the motor 15 remains energized as before, the circuit inchuling the power source 10, ll right-hand blade of the switch 12 conductor 1; terminal 8 of the motor 15, field winding terminal 16 con- The field windthe switch the blade 28, lower contact.of the blade 24, conductor 23 to the other terminal 21 of the armature. Since the field winding of the motor 15 is energized and the armature thereof is short-circuited, the motor 15 acts as a dynamic brake for the shaft 20. At the same time the opening of the switch blade 76 tie-energizes the brake magnets 72, 75 thus applying the brakes and rings the respective reels to a stop.

' Current also flows from the conductor 13 through the resistance 55, lower contact and switch blade 53 of the switch 25, conductor 52, collecting brush of the motor 47, field winding thereof, terminal 51, conductor 56 blade 57, lower contact of the blade 57, left- ,liand blade of the switch 12 to the power source, thus energizing the field winding of the motor 47. he current flowing in the contact of connected by way of conductor 65, blade (3% of the switch 25, contact 68 thereof, conductor 59 to the other armature brush 61 of the motor 47. Thus relative rotation of the shafts 43 and 44 is effectively prevented, the motor 47 serving as a magnetic coupling between these two shafts.

\Vhen the parts have been broughtto a full stop the switches are again placed in their open position thus de-energizing the circuits and restoring the condition for a subsequent operation.

The reel 73 is now removed from the shaft 44 and the wire is another reel, such as the reel pose of reproducing the recorded sound. The switch 84 is now thrown into its upper position thus connecting the magnets 80, 81 into circuit with a telephone receiver 88. The receiving device 88 may take any desired for example a loud speaker, and in the circuit if desired an amplifying device for amplifying the energy. The wire is now run as before and induces in the magnets 80, 81 undulatory currents corresponding original currents, which caused. the record to be made. The receiver 88 responds to these currents and produces in the surronmling atmosphere compressional waves similar in character to the original compressional Waves, which actuated the transmitter 80 when making the record.

The invention upon which this application is based is broader than the specific embodiment shown and described for the purpose of illustrating at least one of the ways in which it may be employed. The scope of the invention is, therefore, to be understood as not being cut specific description. I intend no limitations other than those imposed by the claims.

hat is claimed is:

1. A power drive system comprising a motor, a grooved drum rotated thereby for actuating a wire, a take up reel for the wire, from which the wire is fed, d means interconnecting said reels comprising a motor having its connected to one of said reels and its field connected to the other reel.

2. A power drive system comprising a motor, a grooved drum rotated thereby for actuating a wire, a take up reel for the wire, a follower reel from which the wire is fed,

direct armature for ier of said reels.

3. In a, telegraphone, two alined shafts, a reel on each of said shafts each rotatable with its respective shaft, means operatively connected to one of said shafts for producing a magnetic field, an armature responsive to field operatively connected to the other (1 a recording body unwound from upon said reels respectively.

Signed at New York, '1 the county of New York and State of New York, this 21st day of February, A. D. 1927.

MILLER REESE HUTCHISON.

limited by the pres 

